Vulnerability Report

CVE-2026-33806

Title: Fastify Content-Type Validation Bypass

Other

Proof Of Concept

No public PoC currently indexed for CVE-2026-33806.

CWE Category CWE-1287
Published Date Apr 15, 2026
Modified Date Jul 15, 2026
Exploit Status Not Found
Score 7.5 CVSS v3.1
Exploit Probability (EPSS)
0.41%

Vulnerability Summary

CVE-2026-33806: Impact: Fastify applications using schema.body.content for per-content-type body validation can have validation bypassed entirely by prepending a space to the Content-Type header. The body is still parsed correctly but schema validation is skipped. This is a regression introduced in fastify >= 5.3.2 by the fix for CVE-2025-32442 Patches: Upgrade to fastify v5.8.5 or later. Workarounds: None. Upgrade to the patched version.

Impacted Vendors

F
fastify 1

Reference Links

https://cna.openjsf.org/security-advisories.html https://github.com/fastify/fastify/security/advisories/GHSA-mg2h-6x62-wpwc
CVSS v3.1
Source Entity ce714d77-add3-4f53-aff5-83d477b104bb
Severity HIGH
7.5
Attack Vector
NETWORK
Complexity
LOW
Privileges
N/A
Interaction
NONE
Confidentiality
N/A
Integrity
N/A
Availability
N/A
Scope
UNCHANGED
RAW VECTOR CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
CVSS v3.1
Source Entity 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
Severity HIGH
7.5
Attack Vector
NETWORK
Complexity
LOW
Privileges
N/A
Interaction
NONE
Confidentiality
N/A
Integrity
N/A
Availability
N/A
Scope
UNCHANGED
RAW VECTOR CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N

Associated Attack Patterns (CAPEC)

Total: Patterns

CVE-2026-33806 Exploits & PoCs (Proof Of Concept)

No public PoCs found in our database for this CVE.

MODIFIED

Vulnerability data updated via NVD.

MODIFIED

Vulnerability data updated via NVD.

MODIFIED

Vulnerability data updated via NVD.

MODIFIED

Vulnerability data updated via NVD.

Attack Vector Matrix

Access Vector NETWORK
Complexity LOW
Privileges N/A
Interaction NONE
CVSS Vector String CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N

Affected Stack

No specific products linked.